 In the rover head, it takes a while, it's 2 years. So you need to make sure the bubble inside the seat belt, right? Yeah, so there's an electronic level on here too, on the controller, and it matches up with this one here. So we have the elevation here, 2.6. How many hours this battery? We never usually run out, we just usually be able to finish our survey before it dies. The one that actually dies faster is the base. It dies because it's like constantly talking to the...